Rapid analysis of aflatoxins in raw peanuts,corn, buckwheat and red pepper by a new mini-column cleanup and HPLC using post-column photochemical derivatization system

A rapid and clean method for the analysis of aflatoxins (AFs) was developed by using a new column and post-column photochemical derivatization HPLC with fluorescence detection. The new cleanup column consisted of magnesia and basic alumina poured on the top of a commercial multi-functional mini-column. It was extremely effective for the cleanup of AFs from raw peanut, corn, buckwheat and red pepper. Fluorescent substances, which interfered with the analysis of AFs from corn, were completely absorbed at the top of the magnesia layer. Recoveries of AFs (B1, B2, G1, G2) added to raw peanuts, corn, buckwheat and red pepper were over 80% at two levels of fortification (higher level: 10, 3, 10, 3 ng/g, respectively, lower level: 1.0, 0.3, 1.0, 0.3 ng/g, respectively). Coefficients of variation were smaller than 12%, except the lower fortified level for red pepper. Limits of detection for AFs in raw peanuts, corn and buckwheat were 0.3 ng/g for B1 and G1, and 0.1 ng/g for B2 and G2. Those in red pepper were 0.5 ng/g for B1, B2, G1 and G2.